It is extremely difficult to deliver enhanced whitening, especially rapid whitening, from a rinse-off composition. The optical modifiers delivering these properties are not readily deposited, are readily rinsed of and, because they readily agglomerate, are not in a sufficiently dispersed state to be efficiently delivered to substrate (which is another way to say that they rinse off too easily).
Applicants' co-pending U.S. Ser. No. 10/241,401 to Zhang et al., filed Sep. 11, 2002 discloses personal care formulations comprising particles of defined refractive index, thickness, geometry and size. While this disclosure relates to how size, shape, etc. of the particles themselves help deposition (and thus shine), it fails to disclose specific deposition enhancement systems (e.g. based on type of surfactant and/or polymers), and the use of dispersed, sub-micron TiO2 (preferably with other optical modifiers) to deliver enhanced whiteness. It also does not disclose how particles must be adequately dispersed on substrate (e.g., skin) to deliver defined change values needed to perceive measure optical traits.
U.S. Ser. No. 10/443,396 to Zhang et al., filed May 23, 2003 discloses structured benefit agent for enhanced delivery of optical modifier, but again does not disclose combination of sub-micron titanium dioxide, cationic deposition polymers (forming precipitates as deposition aid) and adequate dispersal to deliver enhanced whiteness.